Completely resorbable connective tissue distraction devices and techniques

ABSTRACT

One aspect of the present invention is a connective tissue distraction device comprising: a first transmitting structure for transmitting force to a first tissue region and a second transmitting structure for transmitting force to a second tissue region by contact with bone, and an expansion device for exerting force distracting the first transmitting structure from the second transmitting structure. At least one of the first transmitting device, the second transmitting device and the expansion structure comprises in whole or in part a biodegradable, bioerodible or bioresorbable material.

This application claims benefit of priority to U.S. provisional patentapplication No. 60/170,011, filed Dec. 9, 1999 to Cohen et al., which isincorporated by reference herein in its entirety.

TECHNICAL FIELD

The present invention generally related to devices and methods ofdistraction, particularly of connective tissue such as bone, such as ina human subject. Preferably, the devices and methods are used in humancraniofacial bone distraction.

BACKGROUND OF THE INVENTION

Connective tissue is the tissue that binds together and supports thevarious structures of the body. It has been demonstrated that gradualapplication of force separating two or more portions of a canine orhuman connective tissue structure will result in deposition of extracellular fibrous tissue components with permanent increase in tissuesize and mass. E.g., Karp, N. S., McCarthy, J. G., Schneiber, J. S.,Sissons, H. A., and Thome, C. H. M., “Membranous Bone Lengthening: ASerial Histological Study,” 29 Ann. Plast. Surg. 2-7 (1992); andCostantino, P. D. and Freidman, C. D., “Distraction Osteogenesis,” 24Otolaryngologic Clinics of N.A. 1433-43 (1991) (“Costantino et al.”). Insome instances this has been facilitated by cutting or breaking thetissue intermediate the tissue areas where force is applied byperforming an osteotomy or corticotomy. In other instances, particularlyinvolving growing tissue, such cutting or breaking is not necessary.

For instance, human bone lengthening by gradual distraction wasdemonstrated at least as early as 1905, but it has been more widelypracticed only more recently, having been popularized by Ilizarov inRussia and De Bastiani and his associates in Italy. See McCarthy, J. G.,Schneiber, J., Karp, N., Thorne, C. H., and Grayson, B. H., “Lengtheningthe Human Mandible by Gradual Distraction,” 89 Plast. And Reconstruct.Surg. 1-8 (1992) (“McCarthy et al.”); and Ilizarov, “The Principles ofthe Ilizarov Method,” 48 Bull. of the Hospital for Joint DiseasesOrthopaedic Institute 1-11 (1988). Gradual distraction offers distinctadvantages as compared to bone grafting. Taylor, Discussion of McCarthyet al., 89 Plast. and Reconstruc. Surg. 9-10 (1992):

It provides new living bone of similar character, the soft tissues arelengthened without loss of sensation, there is no donor-site morbidity,and the technique may stimulate the efficiency of the reduced functionalmatrix in the region. Id. At 10.

Most bone lengthening and corrective work has been done with respect tolong bones in the arms and legs, although McCarthy, et al. havedemonstrated that the mandible of human children can be lengthened bygradual distraction. See also Senezer, M., “Mandibular Lengthening byGradual Distraction,” 92 Plast. and Reconstruct. Surg. 372 (1993)(reporting lengthening of human adult mandibles).

Additionally, devices utilizing screw or other expansion mechanismsattached between and solely to the left and right maxillary teeth havebeen used in procedures that enlarge human palates. e.g, Epker, B., andFish, L., 2 Dental Facial Deformities 818-875 (1986). At least some suchprocedures commence with substantial expansion of the maxilla during theinitial surgical procedure. Id. At 831.

The mandibular distraction device utilized by McCarthy, et al., is arelatively large appliance mounted outside the patient's mouth on pinsthat pass through incisions in the cheek. Such distraction devices areheavy, unwieldy, unsightly and subject to damage or dislocation impact.Furthermore, such devices require incisions that leave scars that may beunsightly and require revision. As McCathy et al. have noted, bettermandibular distraction devices are needed for these and other reasons.See also Costantino et al. at 1441; and Karp, N. S., Thome, C. H. M.,McCarthy, J. G., Sissons, H. A., “Bone Lengthening in the CraniofacialSkeleton,” 24 Ann. Plast. Surg. 231, 236 (1990). Furthermore, gradualdistraction of other craniofacial sites is desirable but generally hasnot been possible because of the limitations of existing devices.

Early midface distraction with buried devices were being performed invarious centers by about 1993 (Cohen et al., J. Craniofac. Surg. 6:368etc. (1995); Muhlbauer, Reconstructive and Aesthetic Surg. Meeting,Yokahoma, Japan, April 1995 (abstract)). Molina performed high Le Fort Iosteotomoies and midface distraction by a reverse headgear that had thecharacteristics of a tooth-borne appliance (Molina, Workshop onDistraction of the Craniofacial Skeleton, New York University MedicalCenter, New York, N.Y., Mar. 18-19 (1994)). In addition, buried midfacedistraction was performed in a child with anophthalmia and leftcraniofacial micrisomia (Cohen et al., Craniofac. Sur. 6:368 etc.(1995)). In this instance, the outcomes were documented by cephalogramsand coronal or three-dimensional computed tomographic scans. Muhlbauerconducted a series of Le Fort III and monobloc distraction in patientswith Apert's syndrome (International Meeting of Plastic, Reconstructive,and Aesthetic Surgery in Yokohama, Japan (1995)). Chin and Toth reportedburied distraction, including Le Fort III midfacial advancement (Chinand Toth, J. Oral Maxillofac. Surg. 54:45 etc. (1996)). Polley et al.,using an external traction appliance, showed frontofacial advancement ina newborn with proptosis and upper airway obstruction (Polley et al., J.Craniofac. Surg. 6:421-423 (1995)). Buried modified Le Fort III midfaceadvancements having cleft lip and palate with midface hypoplasia andClass III maloccluson have been performed (Cohen et al., Plast.Reconstr. Surg. 99:1421-1428 (1997)). In these cases, transversemaxillary expansion was performed with sagittal distraction and in onecase serial distractors were used to provide vertical and horizontaldistraction vectors. In other cases, a subtotal cranial vault reshapingand monobloc facial advancement was performed in a child who hadPfeiffer's syndrome and coreal exposure (Cohen et al., Plast. Reconstr.Surg, 101:1919-1924 (1998)). In that case, after 28 mm of distraction,the proptosis was largely corrected. Chin and Toth have reported Le FortIII advancement with gradual distraction using internal devices in aseries of patients using a method of rapid distraction (Chin and Toth,Plast. Reconstr. Surg. 100:819-830 (1998)). Polley and Figueroa reportedthe management of maxiallary deficiency in childhood and adolescence byperforming distraction osteogenesis with an external adjustable, rigiddistraction device to provide improvement in cleft lip, cleft palate andsevere midface retrusion (Polley and Figueroa, J. Craniofac. Surg.78:181-185 (1997); See generally Cohen, Seminars in Orthodontics,5:52-58 (1999)).

Additional explanation of the conditions addressed by the presentinvention and, in some instances, more specific information about priorremedial practices is set forth together with the descriptions ofexemplary embodiments of the present invention provided below.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a perspective view depicting the two portions of atransmitting means being engaged using PLA/PGAs screws.

FIG. 2 is a plan view depicting two transmitting means of FIG. 1 engagedwith an expansion means.

FIG. 3 is a perspective view depicting the nature of the engagement ofthe transmitting means and the expansion means as reversible.

FIG. 4 is a perspective view depicting the distraction device in placeat the site of osteotomy. Th transmitting means are secured to the skullusing PLA/PGA screws in holes drilled into the bone. During adistraction procedure, the implementation of the distraction devicewould be complete. Distraction would be accomplished by engaging theexpansion means with an activation means to gradually increase thedistraction distance.

FIG. 5 is a perspective view depicting the distraction device afterdistraction has taken place. This figure depicts a mock-up skull, thusthe distraction space has not been filled with distraction tissue. Atthe point in the procedure, the expansion means would be removed bydisengaging the expansion means from the transmitting means, such as byengaging the activation means to decrease the length of the expansiondevice. The expansion means can be removed using surgical procedures,preferably endoscopic procedures. If the expansion means is made inwhole or in part of biodegradable, bioerodible or bioresorbablematerials, then the expansion me can optionally be removed. Optionally,at least one stabilizer can be inserted into, over or around theexpansion space and appropriately secured such that the distractedtissue is mechanically stabilized. Such stabilizer(s) are preferablymade at least in part of biodegradable, bioerodible or bieresorbablematerial, such as PLA/PGA, preferably macroporous PLA/PGA.

FIGS. 6A, 6B and 6C are top, bottom and side views depicting aflange-engaging structure of a transmitting means of one aspect of thepresent invention that includes structures to engage an expansion means.

FIG. 7 is a conceptual diagram depicting the use of stabilizing means ina distraction procedure.

FIG. 8 is a conceptual diagram depicting the use of guiding means todirect the vector of distraction.

FIG. 9 is a conceptual diagram depicting the use of stabilizing means ina distraction procedure.

FIG. 10 is a conceptual diagram depicting the use of engagingstructures, such as in a “shark's tooth” configuration, that allowsmembers of the distraction device to slide against each other in aunidirection manner, which can also serve to stabilize the distractiondevice itself.

SUMMARY OF THE INVENTION

The present invention recognizes that existing distraction devices havecertain disadvantages, including the requirement to remove materials inthe distraction device from the subjects body after distraction iscompleted. Depending on the location of distraction, this procedure canbe of varying degrees of undesireability, such as due to difficulties ofremoval procedures and discomfort to the subject.

A first aspect of the present invention is a connective tissuedistraction device comprising: a first transmitting means fortransmitting force to a first tissue region and a second transmittingmeans for transmitting force to a second tissue region by contact withbone, expansion means for exerting force distracting said firsttransmitting means from said second transmitting means, wherein at leastone of said first transmitting means, said second transmitting means andsaid expansion means comprises in whole or in part a biodegradable,bioerodible or bioresorbable material. Preferably two or more of theseelements include in whole or in part such biodegradable, bioerodible orbioresorbable materials. Optionally, all three of these elements includein whole or in part such biodegradable, bioerodible or bioresorbablematerials. In one preferred aspect of the present invention, theexpansion means is not integral to at least one of or both of the firsttransmitting means or the second transmitting means.

A second aspect of the present invention is a method of distracting afirst tissue region and a second tissue region, comprising: implantingthe connective tissue distraction device of the present invention into asubject and distracting the first tissue region and the second tissueregion.

A third aspect of the present invention is a device for stabilizing orearly stabilization of distracted connective tissue that includes abiodegradable, bioerodible or bioresorbable material engaged on or neardistracted connective tissue.

A fourth aspect of the present invention is a method for stabilizing orearly stabilization of distracted connective tissue using a stabilizerthat includes a biodegradable, bioerodible or bioresorbable materialengaged on or near distracted connective tissue.

A fifth aspect of the present invention is a method for stabilizing orearly stabilization of distracted connective tissue that includesproviding biodegradable, bioerodible or bioresorbable materials, such asmesh, plates or macroporous plates at or near the site of distractionbefore, during or after distraction procedures such that protected boneregeneration of the distraction callus can is accentuated.

The methods and devices of the present invention utilize small single ormultiple action expansion structures attached to anchoring or pressureexerting members gradually to distract bone or other connective tissuein order to increase tissue length and mass. Generally, at least one ofthe members in each device is fixed in place, such as with screwspassing into bone, by attachment to teeth, with staples passing intobone, using appropriate glues or adhesives, or by engaging anothermember of the device of the present invention. Such fixing means,methods or structures, such as pins, screws or staples, can include inwhole or in part biodegradable, bioerodible or bioresorbable materials.In addition, at least a portion of at least one member in each apparatusis preferably at made in whole or in part made of biodegradable,bioerodible or bioresorbable material. At least a portion of theapparatus of the present invention can be positioned subcutaneously orinside the patient's mouth in the case of intraoral or partiallyintraoral devices, thereby avoiding the need to penetrate the cheek.Preferably, the only portion of the device that is present outside ofthe body of a subject is a portion of an activating means that is usedto actuate a device of the present invention to alter the spacialrelationship of at least two members of an apparatus of the presentinvention. Portions or all or most such intraoral devices are positionedunder the soft tissue that overlies bone being corrected. At othercraniofacial sites, the entire device is positioned under overlying softtissue, with a very small window or penetration through which theexpansion mechanism is manipulated. Preferably, biodegradable,bioerodible or bioresorbable materials are provided under soft tissuesrather than external to the subject, but that need not be the case. Forexample, certain biodegradable, bioerodible or bioresorbable materialsmay not be appropriate for use inside the buccal cavity due to moistureand biological activities, such as enzymatic activities, that may hastenthe erosion of such materials. However, certain biodegradable,bioerodible or bioresorbable materials may be well-suited to extendexternal of the skin surface, such as in the cranio-facial region. Forexample, means to manipulate expansion means may be made of suchbiodegradable, bioerodible or bioresorbable materials and can externalto the skin surface, such as through the scalp, such as behind an ear.

The use of the devices of the present invention reduces the physical andemotional trauma resulting from the distraction procedure and visibilityof the distraction apparatus, reduces scarring, and permits distractioncorrective procedures to be performed that were not previously possible.The present invention permits treatment of a wider variety ofcraniofacial deformities than was previously possible, includingdeformities of both traumatic and congenital origin, where greater bonelength or mass, or additional other connective tissue, is required in aparticular area.

As will be readily understood by those skilled in the art, a widevariety of conditions, typically involving congenital deformities, canresult in the need for greater bone length or the presence of more boneor other connective tissue in a particular area. The exact nature ofsuch conditions will vary widely from patient to patient, requiring thatthe geometry of the embodiments of the present invention described belowbe modified to accommodate the condition being addressed. The articlesof manufacture and methods of the present invention can be used in anydistraction procedure, including bone, preferably, but not limited tothe craniofacial region and long bones, such as arm and leg.

The structures of the devices and practice of the techniques of thepresent invention will be more fully understood by reference to thefollowing figures and detailed descriptions of the embodiments of theinvention illustrated in these figures.

DETAILED DESCRIPTION OF THE INVENTION

Definitions

Unless defined otherwise, all technical and scientific terms used hereinhave the same meaning as commonly understood by one of ordinary skill inthe art to which this invention belongs. Where a term is provided in thesingular, the inventors also contemplate the plural of that term.

“Connective tissue” as used herein shall mean the tissue that bindstogether and supports the various structures of the body. In particular,“connective tissue” includes collagenous, elastic, mucous, reticular,and cartilaginous tissues, and preferably includes osseous tissue andbone.

A “transmitting means” refers to a structure that is preferably attachedto a tissue region that is to be involved in a distraction procedure.The transmitting means can be made of any appropriate materials,including, but not limited to metals, ceramics, glass, bioglass,biodegradable, bioerodible, bioresorable materials and the like.Preferably, a transmitting means is made of a biodegradable, bioerodibleor bioresorbable material, such as the material described in U.S. Pat.No. 5,919,234 to Lemperle et al., issued Jul. 6, 1999, and as availablefrom MacroPore (San Diego, Calif.). Additional materials include lacticacid polymers as they are known in the art, such as PLAGA or PLA/PGA(poly-(lactic acid-glycolic acid)). Any appropriate biodegradable,bioerodible or bioresorbable materials can be used, so long as they havethe desired characteristics, including biocompatablility and strength.Although the materials described in U.S. Pat. No. 5,919,234 areperforated, that is not a requirement of the present invention.Additional materials, such as PLA/PGA can also be used. Moreover, atransmitting means is preferably heat malleable such that the materialis malleable at a temperature above that of the normal body temperature(such as a glass transition temperature at about 55° C. to 57° C. orgreater, though the invention is not limited to such ranges oftemperatures) and is rigid at body temperature (such as about 55° C. to57° C. or less, though the invention is not limited to such ranges oftemperature). The glass transition temperature of the material ispreferably such that the malleable material, when contacted with atissue or organ, that tissue or organ is not appreciably damaged.

A transmitting means 10A, 10B (collectively 10) can be made of one ormore components that can be engaged form a transmitting means, such asset forth in FIGS. 1 and 2. The transmitting means preferably engages anexpansion means 12 such that distraction is enabled by separating afirst transmitting means 10A from a second transmitting means 10B by anexpansion means 12 such as set forth in FIG. 2.

The transmitting means can be of any appropriate configuration, such as,for example, plates, stents, meshes or implants of any appropriateconfiguration. The transmitting means can have any appropriate shape,such as circular, oblong, polygonal, square or rectangular and can becut to fit using appropriate cutting devices, including shearing devicessuch as scissors, or heating devices, such as a wire heated to anappropriate temperature to cut or trim the transmitting means. Atransmitting means can be attached to a tissue region using anyappropriate attachment structures, devices or means, such as, forexample, screws, staples, tacks, pin, nails or implants of anyappropriate configuration or the like, wherein such materials can bemade of any appropriate material, preferably made at least in part of abiodegradable, bioerodible or bioresorbable material.

A “tissue region” includes a region of tissue to which an transmittingmeans is attached by an appropriate method, device or structure.Preferably, two tissue regions are adjacent to a site to be distracted.Preferably, a tissue region is a connective tissue, more preferablybone.

An “expansion means” refers to a device for expanding or contracting atleast two transmitting means of the present invention. Preferably, theexpansion means is a screw expansion mechanism. One skilled in the artwould recognize that other mechanisms, either alone or in combination,such as, for example, ratchets, worm-screws, sliding devices,unidirectional sliding devices bidirectional sliding devices,multi-vector sliding devices, rack and pinion devices worm gears and thelike can be used. The expansion means can be made of any appropriatematerials, including, but not limited to metals, ceramics, glass,bioglass, biodegradable, bioerodible, bioresorable materials and thelike. Preferably, a transmitting means is made of a biodegradable,bioerodible or bioresorbable material, such as the material described inU.S. Pat. No. 5,919,234 to Lemperle et al., issued Jul. 6, 1999, and asavailable from Macropore (San Diego, Calif.). Additional materialsinclude lactic acid polymers as they are known in the art, such as PLAGAor PLA/PGA (poly-(lactic acid-glycolic acid)). Any appropriatebiodegradable, bioerodible or bioresorbable materials can be used, solong as they have the desired characteristics, includingbiocompatablility and strength. Although the materials described in U.S.Pat. No. 5,919,234 are perforated, that is not a requirement of thepresent invention. Moreover, an expansion means is preferably heatmalleable such that the material is malleable at a temperature abovethat of the normal body temperature (such as a glass transitiontemperature at about 55C. to 57C. or greater, though the invention isnot limited to such ranges of temperatures) and is rigid at bodytemperature (such as about 55° C. to 57° C. or less, though theinvention is not limited to such ranges of temperature). The glasstransition temperature of the material is preferably such that themalleable material, when contacted with a tissue or organ, that tissueor organ is not appreciably damaged.

“Biodegradable” refers to a structure or material that, over time, canbe removed by biological action within the body of a subject such asthey are known in the art or later developed. Biodegradable material caninclude a bioactive compound, such as a pharmaceutical composition, aprotein, a peptide, a nucleic acid molecule or a small molecule. Suchbioactive compounds preferably have desirable activities associated withdistraction procedures, such as growth factors of various types, bonemorphogenic proteins, antibiotics or other compounds to improve orhasten the bone consolidation period or to decrease the time ofdistraction. These bioactive compounds can be leached from thebiodegradable materials over time or be released as the biodegradablematerials is removed by biological action.

“Bioerodible” refers to a structure or material that, over time, can beat least partially removed by biological action within the body of asubject. Preferably, bioerodible materials are removed from the body ofa subject by biological action within between about one month to aboutone year, preferably between about three months and about nine months ofimplantation such as they are known in the art or later developed.Bioerodible material can include a bioactive compound, such as apharmaceutical composition, a protein, a peptide, a nucleic acidmolecule or a small molecule. Such bioactive compounds preferably havedesirable activities associated with distraction procedures, such asgrowth factors of various types, bone morphogenic proteins, antibioticsor other compounds to improve or hasten the bone consolidation period orto decrease the time of distraction. These bioactive compounds can beleached from the bioerodible materials over time or be released as thebiodegradable materials is removed by biological action.

“Bioresorbable” refers to a structure or material that, over time, canbe at least partially removed by biological action within the body of asubject. Preferably, bioresorbable materials are at least partiallyremoved from the body of a subject by biological action within betweenabout one year and about ten years, preferably between about two yearsand about five years of implantation such as they are known in the artor later developed. Bioresorbable material can include a bioactivecompound, such as a pharmaceutical composition, a protein, a peptide, anucleic acid molecule or a small molecule. Such bioactive compoundspreferably have desirable activities associated with distractionprocedures, such as growth factors of various types, bone morphogenicproteins, antibiotics or other compounds to improve or hasten the boneconsolidation period or to decrease the time of distraction. Thesebioactive compounds can be leached from the bioresorbable materials overtime or be released as the biodegradable materials is removed bybiological action.

Biodegradable materials, bioerodible materials and bioresorbablematerials for use in the present invention can be selected from thoseknown in the art or later developed based on their particular biologicalproperties and physical properties. For example, materials preferablyare biocompatble in that they do not stimulate a sustained orsignificant adverse biological response, such as an immunologicalresponse, such as an undesirable macrophage response. Such materials canbe selected using methods known in the art, such as implantation intotest animals or reviews of the literature. Materials preferably haveappropriate tensile strength to withstand the stressed generated duringdistraction. Such materials can be selected using appropriate methods,such as strength determinations or reviews of the literature.

A variety of materials, including polymers such as synthetic polymers ornatural polymers, can be suitable for use in the present invention. Forexample, polymers of the following classes are preferred: bioabsorablebi-component polymers, bacterial polymers and copolymers such aspoly-beta-hydroxy alkonates, polyurethanes, fiber reinforced polymers,self-reinforced polymers, and alpha-hydroxy carbonic acids. Preferredpolymers can also include: Polymers issued from glycolic acid and lacticacids (PLAGA or PLA/PGA) (Vert et al., J. Controlled Release 53:85-92(1998); polylactic acid (J. Oral Maxillofac. Surg. 56:616-626 (1998);collagens, aliphatic polyesters, poly(glycolic acid), poly(lactic acid),poly(epsilon-caprolactone) (Hutmacher et al., Int. J. Oral Maxillofac.Implants 11:667-678 (1996); coral/poly(DL-lactic acid) (Li et al., J.Biomater. Sci. Polym. Ed. 7:817-827 (1996); lactic acid polymers (Merloxet al., Rev.Chir. Orthop. Reparatrice Appar. Mot 81:433-444 (1995);co-polymer 85/15 D,L lactide/glycolide (Balch et al., Arthroscopy15:691-708 (1999); McGuie et al., Arthroscopy 15:463-473 (1999); Kumaret al., J. Craniofac. Surg. 8:97-99 (1997); Pietrazak et al., J.Craniofac. Surg. 8:92-96 (1997); Sinha et al., Drug Dev. Ind. Pharm24:1129-1138 (1998); Tharanon et al., J. Craniofac. Surg. 9:441-444(1998). Preferred polymers are of the class of polyhyproxyorthoesters assupplied by Boehringer Ingelheim.

Additional materials, such as polymers, that may be suitable for use inthe present invention are described in the patent literature: U.S. Pat.No., 5,919,234 to Lemperle, issued Jul. 6, 1999; U.S. Pat. No.5,935,594, issued to Ringeisen et al., issued Aug. 10, 1999; U.S. Pat.No. 5,935,594 to Ringeisen et al., issued Aug. 10, 1999; U.S. Pat. No.5,876,452 to Athanasiou et al., issued Mar. 2, 1999; U.S. Pat. No.5,766,710 to Turnlund et al., issued Jun. 16, 1998; U.S. Pat. No.5,981,619 to Shikinami et al., issued Nov. 9, 1999 (cyrstallinethermoplastic polymer material, polylactic acid, polyglycolic acid,lactic acid-glycolic acid copolymer and polydioxanone, hydroxylapatite(synthetic or natural, optionally in small amounts); U.S. Pat. No.5,866,155 to Laurencin et al., issued Feb. 2, 1999 (syntheitichydroxyapatite, tricalcium phosphate); U.S. Pat. No. 5,697,976 toChesterfield et al., issued Dec. 16, 1997 (polymethylmethacrylate,polymeric hydroxyethylmethacrylate); U.S. Pat. No. 5,876,452 toAthanasiou et al., issued Mar. 2, 1999 (polyanhydrides, poly(orthoesters), aliphatic polyesters, polylactic acid, polyglycolic/polylacticacid mono-and-copolymers); U.S. Pat. No. 5,252,523 to Beall et al.,issued Oct. 12, 1993 (bioabsorable chlorophosphate and glass-polymerblends); U.S. Pat. No. 5,997,568 to Liu (dioxanone articles, Dexon,Vicryl and Polysorb materials))

A “subject” refers to a human or non-human subject. Non-human subjectscan include experimental, test, agricultural, entertainment or companionanimals.

“Early stabilizing” refers to the stabilization of distracted connectivetissue at a time earlier that expected. Early stabilization can beaccomplished using methods of the present invention. Such stabilizationcan be accomplished, for example, by the early formation of distractedtissue, early differentiation of distracted tissue, or in the case ofbone, early mineralization of tissue.

“Distracted connective tissue” refers to the tissue formed duringdistraction procedure. In the case of bone, distracted connective tissuetends to form a somewhat unstructured, and thus soft, mass, which oftentakes time to strengthen, such as through mineralization.

Introduction

The present invention recognizes that existing distraction devices havecertain disadvantages, including the requirement to remove materials inthe distraction device from the subjects body after distraction iscompleted. Depending on the location of distraction, this procedure canbe of varying degrees of undesireability.

As a non-limiting introduction to the breadth of the present invention,the present invention includes several general and useful aspects,including:

1) a connective tissue distraction device including a first transmittingmeans for transmitting force to a first tissue region and a secondtransmitting means for transmitting force to a second tissue region suchas by contact with bone, expansion means for exerting force distractingsaid first transmitting means from said second transmitting means,wherein one, two or all of said first transmitting means, said secondtransmitting means and said expansion means comprises in whole or inpart a biodegradable, bioerodible or bioresorbable material, preferably,the expansion means is not integral to one or both the firsttransmitting means or the second transmitting means;

2) a method of distracting a first tissue region and a second tissueregion, including implanting the connective tissue distraction device ofthe present invention into a subject and distracting the first tissueregion and the second tissue region;

3) a device for early stabilizing of distracted connective tissue thatincludes a biodegradable, bioerodible or bioresorbable material engagedon or near distracted connective tissue;

4) a method for early stabilizing of distracted connective tissue usinga device that includes a biodegradable, bioerodible or bioresorbablematerial engaged on or near distracted connective tissue; and

5) a method for early stabilizing of distracted connective tissue thatincludes providing biodegradable, bioerodible or bioresorbablematerials, such as mesh, plates or macroporous plates at or near thesite of distraction before and/or during and/or after distractionprocedures such that protected bone regeneration of the distractioncallus can is accentuated.

I. A Connective Tissue Distraction Device

The present invention includes a connective tissue distraction devicethat includes a first transmitting means for transmitting force to afirst tissue region, second transmitting means for transmitting force toa second tissue region and expansion means for exerting forcedistracting said first transmitting means from said second transmittingmeans. Preferably, one, two or all of said first transmitting means,said second transmitting means and said expansion means comprises inwhole or in part a biodegradable, bioerodible or bioresorbable material.Optionally, the expansion means is not integral to one or both of thefirst transmitting means or the second transmitting means.

The first transmitting means and/or the second transmitting means can bethe same or different in any regard, including size, shape andmaterials. The transmitting means can include a structure for attachmentto a tissue region, such as a connective tissue such as bone. Suchstructures can include at least in part a biodegradable, bioerodible orbioresorbable material. Such structures can take any appropriateconfiguration such as those as discussed herein, but preferably include,for example, a plate, including a macroporous plate or a mesh. Thestructure for attachment to a connective tissue is attached to a tissueregion via at least one appropriate attaching device, method or means.Preferred attaching structures include screws, staples, pins or stents.The attaching structures are preferably at least in part biodegradable,bioerodible or bioresorbable material and may be adapted to anycommercially available expansion means, including metallic expansionmeans, such as those provided by Leibinger (Carrollton, Tex.) ordescribed in U.S. Pat. No. 5,129,903 to Luhr et al., issued Jul. 14,1992 or U.S. Pat. No. 5,769,850 to Chin, issued Jun. 23, 1998.

The first transmitting means and the second transmitting means arepreferably directly or indirectly engaged or reversibly or irreversiblyengaged to at least one expansion means. The expansion means can be anyappropriate device or structure such as those discussed herein,preferably a screw actuated expansion mechanism, ratchet or slidingplates. Preferably, the expansion means includes in whole or in part abiodegradable, bioerodible or bioresorbable material. The expansionmeans can be modulated to draw the first transmitting means closer orfurther away from the second transmitting means. In doing so, the firsttissue region and the second tissue region are brought closer togetheror further away. Alternatively, a transmitting means and an expansionmeans can be combined into a single structure, such that there is 1) atransmitting means and 2) a transmitting means and an expansion meansthat forms the connective tissue distraction device.

In one aspect of the present invention, the first transmitting means 10Aand the second transmitting means 10B comprise structures that allow thetransmitting means 10 to slide unidirectional across each other. The twotransmitting means 10 can slide along a single vector 14 or multiplevectors based on the articular structures used. For example, the firsttransmitting means 10A can comprise engaging structures designed toengage mating structures on the second transmitting means 10B. Forexample, the first transmitting means 10A can comprise a plurality ofindentations, hole, protrusions, “ark's teeth” or other structures thatcan engage mating structures on the second transmitting means 10B suchas indentations, holes, protrusions or other structures. Preferably, theengaging structures are indentations or holes 16 and the matingstructures are protrusions such as pins or shark's teeth structures 18.Alternatively, the engaging structure and the mating structure shark'steeth structures. As the two transmitting means slide across each otherin one dire on 14, they engage such that they preferentially do notslide in a different direction. One preferred example of the aspect ofthe invention is depicted in FIG. 10.

In another aspect of the present invention, the connective tissuedistraction device includes guiding means 20 to allow distraction toproceed along a pre-determined vector. For example, a guiding means caninclude a variety of structures to engage at least one portion of atleast one transmitting means, such tongue and groove configurations. Theguiding means are preferable made at least in part of a biodegradable,bioerodible or bioresorbable material. One preferred example of thisaspect of the present invention is provided in FIG. 8.

The connective tissue distraction device can further include anactivation means to modulate the expansion means. The activation meanscan be at least in part external to the subject such that thedistraction device can be adjusted without invasive procedures. Theactivation means can be adjusted using additional materials, such asturn-keys, that activate the expansion means. The activation means candirectly or indirectly engage the expansion means, such as by havingadditional structures between the expansion means and the activationmeans (Leibinger MID System, Scientific Documentation, Modular InternalDistraction System, Howmedica Leibinger (1998)).

In one aspect of the present invention, the activation means 22 can beengaged with the expansion means 12 at will, such as where theactivation means can engage the expansion means while within the subjectand then be removed at will. Preferably, the activation means is engagedwith the expansion means only for activating the expansion means andthen is removed. The tissues surrounding the expansion means can bestructured using surgical methods known in the art so that theactivating means and the expansion means can be reversibly engaged.While so engaged, the activation means can activate the expansion means.In one aspect of the present invention, the activation means can includea gear reduction structure, such as between about 1:2 and about 1:50,preferably between bout 1:5 and about 1:20, so that relatively largemovements in the activation means result in relatively smaller movementsin the expansion means. The use of such gear reduction allows foraccuracy and reproducibility in the distances chosen for distractionprocedures. When the activation means is removable at will, it ispreferred that the transmitting means and/or expansion means engageusing structures 16, 18 that encourage unidirectional displacement, suchprovided in FIG. 10.

The activation means 22 need not be permanently engaged with theexpansion means. This is particularly true when the expansion means 12is designed of biodegradable, bioerodible or bioresorbable material andintended to be left in the subject. Under those circumstances, theactivation means is preferably not made of biodegradable, bioerodible orbioresorbable materials can be conveniently disengaged from theremainder of the distraction structure and removed. In this aspect, theportion of the distraction structure remaining within the subjectcomprises in whole or in part biodegradable, bioerodible orbioresorbable materials. In another aspect of the present invention, theactivation means and expansion means are integral to each other can bedisengage from one or more transmitting means and removed (see, FIGS.1-3).

The present invention also includes a connective tissue distractiondevice of the present invention implanted in a subject. When implantedat least on part within the subject, it is preferable that thetransmitting means and the expansion means are internal to the subject.When present, it is preferable that at least a portion of the activationmeans is external to the subject.

II A METHOD OF DISTRACTION

The present invention also includes a method of distracting a firsttissue region and a second tissue region, comprising: implanting theconnective tissue distraction device of the present invention into asubject and distracting the first tissue region and the second tissueregion. The tissue regions are preferably separated, such as by anaccident or by surgical procedures such that bone lengthening is plannedand desired. Tissue regions, such as connective tissues including bonecan be wholly or partially separated using methods known in the art,including osteotomy.

As set forth in FIG. 4, the device of the present invention isappropriately engaged in the subject. The distraction device is thenmodulated using the expansion means 12 and optionally the activationmeans 22 to cause the tissue regions to become further apart. The speedand distance by which the tissue regions are separated by thedistraction device are choices to be made by the surgeon based on theparticular circumstances of a particular case. A rate of distraction ofabout 0.5 mm to about 1.0 mm twice a day is recommended. Distractioncontinues until the desired distraction distance has been achieved orcircumstances dictate otherwise. Then, the freshly deposited tissue,when bone, is allowed to mineralize and thus strengthen.

In the present method, components of the distraction device that are notbiodegradable, bioerodible or bioresorbable are preferably removed afterdistraction is completed. In preferred aspects of the present invention,the transmitting means are made of such biodegradable, bioerodible orbioresorbable materials and thus need not be removed. If the expansiondevice is not made of a biodegradable, bioerodible or bioresorbablematerials, then that device can be removed by surgical or other methods.Preferably, the expansion means is reversed, such as by the activatingmeans, to free the expansion means from the transmitting means. Theexpansion means can then be removed with minimal invasive procedures.

The activating means can be removed independently of the expansionmeans. This is particularly preferable if the expansion means is made ofa biodegradable, bioerodible or bioresorbable material. In thisinstance, the expansion means and activating means are preferablyreversibly engaged by an appropriate structure as they are known in theart, such as, for example, male-female coupling structures.

III Device for Stabilizing or Early Stabilization of DistractedConnective Tissue

The present invention also includes a device for early stabilizing ofdistracted connective tissue. The device includes a stabilizer thatincludes at least in part a biodegradable, bioerodible or bioresorbablematerial engaged on or near distracted connective tissue. The distractedconnective tissue is preferably bone, but can be other connectivetissues. The stabilizer is preferably within a subject. Due to thebiodegradable, bioerodible or bioresorbable material in the stabilizer,the stabilizer will be at least in part absorbed by the subject and notrequire additional surgical procedures.

One preferred aspect of the present invention includes a stabilizer madeof a macroporous biodegradable material, such as through Macropore (SanDiego). The device is preferably designed to engage at least onetransmitting means such that space between transmitting means is spannedat least in part, preferably in whole, by the stabilizer. The stabilizercan be engaged with connective tissue, such as bone, using appropriatematerials, preferably fasteners made at least in part of biodegradable,bioerodible or bioresorbable material. Preferably, the stabilizerreplaces the expansion means when such means are note made ofbiodegradable, bioerodible or bioresorbable materials.

In one aspect of the present invention, the stabilizer replaces at leastone transmitting means and an expansion means. For example, as shown inFIG. 8 the stabilizer would be designed to replace the distal (right)transmitting means and the expansion means by having a shape and sizecorresponding to the combination of the distal transmitting means:expansion means combination. As such, the stabilizer would have a flangethat corresponds to the metal flange that gages the notch in theproximal (left) transmitting means 10A. As shown in FIG. 8 thestabilizer 24 would correspond to the combination in the right hand ofthe model. In this aspect of the invention, the distal transmittingmeans and expansion means would be removed and replaced with thestabilizer. Optionally, the stabilizer would be designed to replace theproximal transmitting means. This is the choice of the surgeon, such ason the invasive nature of the procedure. In the procedure depicted inFIGS. 4 and 5, for example, the procedure is much less invasive toremove or alter the distal transmitting means and as such is preferablyover removing or altering the proximal means.

Optionally, the stabilizer can take the shape of at least a portion ofthe combination of the distal transmitting means expansion meanscombination. In that instance, the distal transmitting means need not beremoved, the expansion means is removed, and the stabilizer is engagedto the connective tissue using appropriate attaching structures 26.Optionally, the stabilizer would be designed to take the shape of atleast a portion of the combination of the proximal transmitting meansexpansion means combination. This is the choice of the surgeon, such ason the invasive nature of the procedure. In the procedure depicted inFIGS. 4 and 5, for example, the procedure is much less invasive tomodulate the area of the distal transmitting means and as opposed to thearea of the proximal transmitting means.

IV Method for Stabilizing or Early Stabilization of DistractedConnective Tissue Using a Stabilizing

Another aspect of the present invention is a method for earlystabilizing of distracted connective tissue that includes performingdistraction on a subject using a distraction device and engaging astabilizer of the present invention with at least one of saidtransmitting means. Preferably, the stabilizer includes at least in parta biodegradable, bioerodible or bioresorbable material, more preferablyof macroporous or other material that promotes bone formation andstrengthening, such as described in U.S. Pat. No. 5,919,234, PLA/PGA oravailable from a variety of commercial sources, such as Macropore (SanDiego, Calif.). Preferably, the stabilizer is engaged on or neardistracted connective tissue such that distracted tissue is supportedand stabilized and allowed to strengthen. The stabilizer can be engagedwith a tissue region using appropriate attachment devices as describedherein, which are preferably made at least in part from biodegradable,bioerodible or bioresorbable materials. The tissue region preferablycomprises connective tissue, such as bone.

One preferred aspect of the resent invention has its basis in theprocedure depicted in FIGS. 4 and 5. Distraction is carried out as setforth in the depicted procedure, resulting in the distraction set forthin FIG 5. The expansion means 12 is removed, which results inunsupported expansion tissue that is relatively weak. A stabilizer 24 ofthe present invention, as discussed above, can be engaged in variety ofconfigurations to replace the expansion means at least in part and/or atleast a portion of at least one of the transmitting means. One preferredaspect of this invention is a stabilize made of macroporous PLA/PGA thatcorresponds roughly to the size and shape of the distal transmittingmeans, the distracted space, and the expansion means, including theflange of the expansion means that engages the slot 26 of the proximaltransmitting means 10A. The distal transmitting means is optionallyremoved, the stabilizer engaged, and the stabilizer preferably engagedwith connective tissue at the location of the distal transmitting meansusing appropriate attachment structures 26 or devices as describedherein. As discussed above, the choice of modulating the proximal ordistal transmitting means is that of the surgeon based on the particularcircumstances of the case at hand, including the relative invasivenature of the locus of the transmitting means, the safety of theprocedure, and the desired result.

In the alternative, a stabilizer of the present invention can bedesigned to be of a variety of shapes, such as strips, that span thedistracted space. In that instance, the strips are positioned to spanthe distracted space and are secured to the tissue, such as bone oneither side of the distracted space. This step can be performed beforeor after the expansion device is removed. Such materials are preferablymade of macroporous PLA/PGA.

Furthermore, at least one stabilizer can be included in the distractiondevice. The stabilizer is preferably made at least in part ofbiodegradable, bioerodible or bioresorbable material, such as PLA/PGA,preferably macroporous strips or meshes of that material. The stabilizercan be fashioned to be a attached to one side of the distraction gap andallowed to slide relatively unabated during the distraction procedure.After distraction is completed, the stabilizer can be attached to theother side of the distraction gap 30. One preferred example of thisaspect of the present invention is depicted FIG 7.

V Method for Stabilizing or Early Stabilization of Distracted ConnectiveTissue Using Biodegradable, Bioresorbable or Bioerodible Materials

Another aspect of the present invention is a method for earlystabilizing of distracted connective tissue that includes providingbiodegradable, bioerodible or bioresorbable materials, such as mesh,plates or macroporous plates at or near the site of distraction beforeand/or during and/or after distraction procedures preferably such thatprotected bone regeneration of the distraction callus can isaccentuated.

1. Stabilizing Distracted Connective Tissue—Pre-Distraction Procedures

One method of the present invention is a method for early stabilizing ofdistracted connective tissue, including: providing at least onebiodegradable, bioerodible or bioresorbable material at or near the siteof distraction before a distraction procedure take place and performingdistraction. The material is preferably a material that encourages bonegrowth, development or strengthening, such as macroporous materials ormeshes of materials (such as those described in U.S. Pat. No. 5,919,234,preferably made of PLA/PGA). The material is preferably malleable, suchas heat malleable or chemical malleable, and can also optionally haveshape memory.

In operation, the site to be distracted is covered at least in part withthe material such that during distraction soft tissues and othermaterials are at least preferentially at least partially kept out of thedistraction space. Such materials are fashioned to the distraction sitebefore or after osteotomy procedures, preferably after such procedures.A distraction device, either of the present invention or otherwise, isthen mounted to the distraction site and distraction takes place asappropriate for the location of the distraction and the type of deviceused. Distraction devices made entirely of metal such as they are knownin the art (see, for example, Leibinger Mid-System documentation90-02104 (December 1998), Howmedia Leibinger, Carrollton, Tex., which isincorporated herein by reference) can be used, as well as thedistraction devices of the present invention. Other distraction devicesknown in the art or later developed can also be used in these methods.The presence of these material is expected to aid in the speed ofdistraction. Although the inventors do not wish to be limited to anyparticular mechanism, enhanced speed of distraction may be attributableto increased speed of bone formation, increased mechanical stabilityprovided by the material, or increased speed of mineralization of thedistracted tissue. In one preferred aspect of the invention, thematerial can form layers which slide against each other as distractionproceeds such that the distraction space is continually covered withmaterial. In one aspect of this invention, for example, a rounded longbone is to be distracted, the first transmitting means can be a firstcylinder and the second transmitting means can be a second cylinder,wherein the first cylinder and second cylinder overlap each other, suchas two tubes of different diameters would. As distraction proceeds, thedistraction space remains covered by the material that overlaps in thetwo cylinders. Of course, this procedure does not require the use ofrounded long bones nor the use of cylindrical transmitting means and theprocedure can be adapted to other configurations, shapes and locations.

Furthermore, at least one stabilizer can be included in the distractiondevice. The stabilizer is preferably made at least in part ofbiodegradable, bioerodible or bioresorbable material, such as PLA/PGA,preferably macroporous strips or meshes of that material. The stabilizercan be fashioned to be attached to one side of the distraction gap andallowed to slide relatively unabated during the distraction procedure.After distraction is completed, the stabilizer can be attached to theother side of the distraction gap.

2. Stabilizing Distracted Connective Tissue—During Distraction

A further method for early stabilizing of distracted connective tissue,including: providing biodegradable, bioerodible or bioresorbablematerials at or near the site of distraction during distraction. Thematerial is preferably a material that encourages bone growth,development or strengthening, such as macroporous materials or meshes ofmaterials (such as those described in U.S. Pat. No. 5,919,234,preferably made of PLA/PGA). The material is preferably malleable,preferably heat malleable.

In operation, a distraction device is implanted at a distraction sitethe site to be distracted using methods appropriate for the site ofdistraction, the method of distraction and the distraction devicechosen. The material can be attached to the site using methods andprocedures described in U.S. Pat. No. 5,919,234. During the distractionprocedure, especially if the distraction procedure is not progressingwell, the distraction site, preferably including distraction tissue iscovered at least in part with the material such that during theremainder of distraction soft tissues and other materials arepreferentially at least partially kept out of the distraction space.Distraction devices made entirely of metal as known in the art can beused, as well as the distraction devices of the present invention. Otherdistraction devices known in the art or later developed can also be usedin these methods. The presence of the material can aid in the speed ofdistraction. Although the inventors do not wish to be limited to anyparticular mechanism, the speed of distraction may be attributable toincreased speed of bone formation, increased mechanical stabilityprovided by the material, or increased speed of mineralization of thedistracted tissue.

3. Stabilizing Distracted Connective Tissue—After Distraction

Another method for early stabilizing of distracted connective tissue,including: providing biodegradable, bioerodible or bioresorbablematerials at or near the site of distraction after distraction has takenplace. The material is preferably a material that encourages bonegrowth, development or strengthening, such as macroporous materials ormeshes of materials (such as those described in U.S. Pat. No. 5,919,234,preferably made of PLA/PGA). The material is preferably malleable,preferably heat malleable.

In operation, the site that has been distracted is covered at least inpart with the material such that soft tissues and other materials arepreferentially at least partially kept out of the distraction space.Such materials are fashioned to the distraction site after distractionis completed. The materials can be fashioned to the location before orafter the distraction device, or a portion thereof, if necessary, hasbeen removed. Distraction devices made entirely of metal as known in theart can be used, as well as the distraction devices of the presentinvention. Other distraction devices known in the art or later developedcan also be used in these methods. The presence of the material can aidin the speed of recovery after distraction is completed. Although theinventors do not wish to be limited to any particular mechanism, thespeed of distraction may be attributable to increased speed of boneformation, increased mechanical stability provided by the material, orincreased speed of mineralization of the distracted tissue.

VI Preferred Aspects of the Present Invention

This section described a variety of distraction devices wherein at leastone of the elements of the device, including attachment devices, is madein whole or in part of a biodegradable, bioerodible or bioresorbablematerial. The choice of which elements of the distraction device whichare to made in whole or in part of a biodegradable, bioerodible orbioresorbable material depends on the location of the element (such asin the buccal cavity, subcutaneously or in contact with bone) and theresult desired by the surgeon and guided by the present disclosure andthe state of the art. For example, the materials described in U.S. Pat.No. 5,919,234 may not be particularly well suited for the buccal cavity.Preferably, plates, support structures such as wires, and means forattaching structures to bone, such as staples, stents, pins and screws,are made in whole or in part of biodegradable, bioerodible orbioresorbable materials. Furthermore, expansion devices can optionallybe made in whole or in part of such biodegradable, bioerodible orbioresorbable materials.

As will be readily appreciated by those skilled in the art, theexemplary embodiments of the present invention described herein areprovided for the purpose of illustrating practice of the invention butare not intended to limit the scope of the following claims. Numerousmodifications and improvements may be made to the invention withoutdeparting from the spirit and intent of the invention or scope of theclaims.

The very nature of the human tissue formation problems the presentinvention addresses involves substantial variation from patient topatient and therefore requires adaptation of the invention to the needsof each patient. Additionally, a variety of known and yet to bedeveloped materials can be used to practice the invention. Appropriatematerials should have the needed mechanical properties andbio-compatibility for the uses described. Among such materialsappropriate for various components of the invention are stainless steel,titanium, and various polymeric materials, including acrylic materialswidely utilized in dental and orthodontic applications.

Commercially available plate components made of stainless steel,titanium, biodegradable, bioerodible or bioresorbable materials as wellas other materials may be used for the plates described above. Examplesof such components include the plate system components available fromSynthes Ltd. (U.S.A.), Howmedica, Walter Lorenz Surgical Instruments,Inc., Leibinger, MacroPore and others. It will be preferable in someinstances to replace the described plates (which normally cannot be leftin the patient permanently) with implantable osseointegrated componentsto which the force exerting components of the present invention can bereattached multiple times.

Expansion mechanisms having different sizes and methods of action thanthose illustrated and described herein can also be used in practicingthe present invention, and expansion mechanisms actuated otherwise thanwith screws may also be appropriate provided that they are sufficientlycompact to permit intraoral or buried installation of the devicescontemplated by the present invention and allow essentially or entirelynon-invasive periodic incremental adjustment as described above. Forinstance, any of the expansion mechanisms, particularly including theexpansion mechanism of buried distraction device, could utilize abevel-gear actuated jackscrew mechanism so that rotation of an actuationscrew by access to the end of its head coaxial with the screw results inexpansion at right angles to the axis of the action screw. In the caseof buried distraction device, this could permit the use of a smallerchimney penetrating the overlying soft tissue or would permit theactuation screw itself to protrude through an appropriately sleevedchimney to make it accessible for adjustment. Similarly, cam-acting,ratchet-acting or ratchet and pawl expansion mechanisms could besubstituted for the screw-actuated mechanisms described above. As analternative to all of these, fluidically actuated expansion mechanismsusing pneumatic or hydraulic cylinders or bladder force-exertingmechanisms could also be used.

A. Intraoral, Internal Mandibular Bone Distraction Device

An intraoral, internal mandibular bone distraction device id positionedon a human mandible. A mandibular bone distraction device performsintroral distraction osteogenesis of the mandible in patients withmandibular bone deficiency from a variety of etiologies including butnot limited to: (1) Hemifacial microsomia; (2) Goldenhar's syndrome; and(3) Mandibular deficiency with retrognathism from any other cause.

The mandibular distraction device includes a first transmitting meansthat attaches to the teeth, such as by bonding or cementing usingappropriate materials. The second transmitting means is preferably aplate that is rigidly attached to the mandibular ramus. The firsttransmitting means and the second transmitting means are engaged with anexpansion means used to effect distraction.

The mandibular distraction device can utilize a miniature screwexpansion mechanism as the expansion means. That expansion means caninclude a female slide that receives a male slide, which is movedrelative to female slide by rotation of a double acting jack screw thathas two oppositely threaded ends, one of which is received in a threadedhole in each slide. The jack screw has centrally located trans-axialholes into which a small pin may be inserted in order to rotate thescrew. Screw expansion mechanisms are referred to as “expansion screws”and may be obtained in a variety of sizes and configurations fromDentaurum, Inc. 10 Pheasant Run, Newtown, Pa. 18940-1819; RMOIncorporated, P.O. Box 17085, Denver, Colo. 80217; and Turotech, P.O.Box 284, Wynnewood, Pa. 19096. Expansion means such as screw mechanismsmay be used singly or in series or parallel where greater expansion isdesired or other conditions dictate in this aspect or other aspects ofthe present invention.

Mandibular distraction device may be unilateral or bilateral where bothsides of the mandible require lengthening. If the mandibular distractiondevice is bilateral, the first transmitting means may extend across allteeth in the mandible if such a configuration is appropriate.

With the patient under general anesthesia, the mandibular distractiondevice is inserted in the patient's mouth, the first transmitting meansis attached, such as by bonding or cement, to the teeth and the platesare rigidly fixed to the mandible with screws after appropriateincisions in overlying soft tissue make the mandible surface accessible.The surgeon also performs a cut in the mandible or an osteotomy proximalto the mandibular dentition, and the bone is gradually distracted byperiodically cranking the screw expansion device. Osteogenesis takesplace by the principle of Ilizarov or bone lengthening, whereby new boneis formed in between the edges of the bones being gradually distracted.

As will be appreciated by those familiar with prior tissue distractiontechniques, the mandibular distraction device eliminates external scars,is easily placed, avoids the need for tissue penetration on the femaleslide of the device by attachment to the teeth rather than to bone,avoids interference with intraoral structures and function because ofits low profile and can be easily modified for other applications andsituations.

B. Intraoral, Internal Maxillary-Zygomatic-Orbital Distraction Device

A variety of conditions result in malformation or improper growth of themaxillary-zygomatic-orbital region. For instance young patients withcleft lip and palate sometimes exhibit improper maxilla growth. Anotherembodiment of the present invention is an intraoral, internalmaxillary-zygomatic-orbital distraction device. This device has avariety of applications in surgically assistingmaxillary-zygomatic-orbital growth in three dimensions. By use of themaxillary-zygomatic-orbital distraction device, gradual distractionosteogenesis may obviate the need for surgery later or reduce its levelof complexity.

The maxillary-zygomatic-orbital distraction device comprises a firsttransmitting means that is attached to teeth and the second transmittingmeans is a plate. The expansion means preferably comprises two screwexpansion mechanisms that are positioned in the upper buccal sulci. Oneside of each of the screw expansion mechanisms is preferably attached tothe first transmitting means affixed to the maxillary teeth with claspsand resin bonding material or bone cement. The other side of eachexpansion means is preferably attached to a second transmitting meansthat takes a form of a plate that is rigidly fixed to the maxilla,zygoma, cranium or orbit as is appropriate for the condition beingtreated. As described above in connection with the plates associatedwith mandibular distraction device, such attachment may be accomplishedwith screws that pass through the plates and into the bone to whichattachment is desired, but any alternative attachment means that resultsin rigid connection between the bone and proximate side of the screwexpansion mechanism will accomplish the desired result. For instance,pins or staples into the bone may also be possible, and adhesive bondingto the surface of the bone may be feasible.

While a maxillary-zygomatic-orbital distraction device is preferablybilateral and utilizes two screw expansion mechanisms as expansionmeans, additional expansion may be desirable in some cases, and only aunilateral device may be required where only distraction of only oneside is desired. Additionally, different positioning of the expansionand second transmitting means such as plates, and different platelengths and shapes may be utilized depending on the site wheredistraction is desired.

The device would be useful for achieving bone growth along a LeFort Iosteotomy. Accordingly, the device is inserted under general anesthesiaand anchored to the maxillary teeth and appropriate bone insubstantially the same manner as the mandibular distraction devicedescribed above. A LeFort I osteotomy is also made and the expansionmechanisms are periodically actuated to permit osteogenesis. As notedabove, the plates can be longer to permit their attachment to thetemporal bones and LeFort II and or LeFort III osteotomies performed toobtain movement of the mid-face and maxilla with osteogenesis at theLeFort II and LeFort III sites.

When maxillary deficiency is corrected, the device can be removed orportions left implanted as osseous implants that can be utilized againif further distraction is necessary.

C. Buried Cranial Distraction Device

A variety of cranial and orbital zygomatic deformities exist, includingbut not limited to: (1) deformational head deformities, (2) torticolliswith deformational head deformities, (3) craniofacial microsomia, and(4) syndromic and nonsyndromic craniosynostosis. In the more commondeformities, the patient presents with an asymmetric head shape becauseof torquing of the cranial base. Generally, the occipital area on oneside is flattened, and there may be contralateral bulging of theforehead with anterior plagiocephaly. In essence, the entire cranialbase is shifted, giving the head a parallelogram shape. The buriedcranial distraction device embodiment of the present invention is usefulin treatment of these deformities.

The internal or buried cranial distraction device of the presentinvention utilized a screw expansion mechanism as an expansion meansattached on each side to the first transmitting means and the secondtransmitting means that take the form of plates that are fixed in placewith screws. The device has a low profile so that it hugs the bone sitewhere it is installed and may be entirely buried under the overlyingsoft tissue. Alternatively, only the plates may be buried and theexpansion means is external to the subject, such as when wires penetratethe soft tissue overlying the bone to which plates are attached so thatexpansion mechanism lies near but outside of such tissue. Where deviceis entirely buried, a small chimney can be formed penetrating the softtissue immediately above the actuation holes in the screw to allowinsertion of an appropriately shaped activator to turn the screw inexpansion means. This chimney may, for instance, be lined with a tube orsleeve of an appropriate material such as a stainless steel tube orDacron, Gortex or other synthetic fabric. It may be covered with asilicon rubber cap or an appropriately formed cover or flap of Dacron,Gortex or other synthetic fabric or sheet material. Multiple devices maybe placed across the open cranial sutures or when osteotomies are usedacross the zygoma or zygomatic-orbital complex if the cheekbone andzygomatic orbital region need anterior repositioning. The geometry ofthe plates may be appropriately configured and dimensioned in a varietyof shapes and sized depending on the skull abnormality present andanchorage needed.

The buried cranial distraction device is placed across cranial suturesor across osteotomy lines (for example, orbital and zygomatic) to permitdistraction osteogenesis. By applying the device across the openlambdoid suture, for instance, and gradually distracting the suture byactuation of the expansion mechanism, new bone is laid in between andthe cranial base is gradually repositioned. Multiple devices may benecessary. For instance, one device may be placed across the lambdoidsuture, while a second device is placed across the coronal suture orperhaps on the zygomatic body and arch.

The current treatment of choice for children with severe recession ofthe orbit and forehead secondary to a deformation and not a fused sutureis surgery if the severity of the deformity warrants it. Thus, byplacement of buried distraction devices that can be engaged throughsmall openings in the scalp, the substantial trauma of a combinedneurosurgical and craniofacial surgical procedure is avoided. Inaddition, more precise manipulation of the cranial base structures, theorbit and forehead and the cheek bone, as well as the occiput, willoccur.

D. Intraorbital Expanding Devices

Patients with microphthalmus or anophthalmia and patients followingenucleation of the globe for a variety of reasons such as trauma,tumors, infection, etc. may require repeated intraorbital prosthesis toprevent cessation of intraorbital growth as the patient ages. A varietyof congenital abnormalities and/or conditions present during childhoodnecessitate placement of a variety of orbital prostheses. Ultimately,the orbital cavity is enlarged to a near symmetric size with acontralateral normal orbit and/or is both orbits are involved to apredetermined adult size. Following this, the permanent orbitalprosthesis can then be placed. In some cases of microphthalmus oranophthalmia, an orbit itself is made with bone grafting and/or bonegrafting in combination with orbital osteotomies for expansion. In thesecases serial prostheses must also be used to prevent contraction ofintraorbital volume. Ultimately, a permanent prosthesis is placed.During serial placement of orbital prostheses, retention of theprosthesis can be a problem. This may lead to repeated extrusion of theorbital prosthesis.

Additional embodiments of the present invention are intraorbitalexpanding devices. Each of the intraorbital expanding devices areessentially hemispherically shaped bodies segmented into multiplesegments, preferably between about two and about six segments, morepreferably between about two and about four segments and most preferablytwo or three segments. The segments can be solid or hollow. As will beappreciated by those skilled in the art, the segments may be formed ofany material having appropriate mechanical characteristics anddemonstrated biocompatibility. The devices are placed surgically afterappropriate impressions of the eye socket have been take and the devicefabricated to fit the patient's eye socket.

A screw expansion mechanism is used as an expansion means and attachessegments to be forced apart by rotation of the expansion means, whichpreferably comprises a screw.

Segments are attached by a two-way screw expansion mechanism that hastwo screws that are oriented and operate at right angles to each other.Thus, expansion mechanism is fixed to segment and movably attached tosegments so that rotation of screw causes segment to move relative tosegment along the axis of screw, and rotation of screw causes segment tomove along the axis of screw, which is perpendicular to the direction ofmovement of segment. Such two-way screw expansion mechanisms, called“multidimensional expansion screws” also may be obtained from one ormore of the sources for expansion screws identified above. An expansionmechanism that may be superior to mechanism in the device would movesegment along a direction separated 120° from the direction of movementof segment.

The intraorbital expander devices may be fixed in the patient's orbit bya variety of means. For instance screws may be passed through thesegments and into the bone against which those segments rest.Alternatively, projections from the segments can lodge in theintraorbital bone as the devices are expanded, staples can extend fromthe segments to impale adjacent bone as the device opens, plates canconnect the segments to adjacent bone, or the segments can be coveredwith a resilient material such as silicone rubber to lock the device inplace as the segments are separated. As will also be appreciated byreference to the anatomy of the human orbit, if the segments areprovided with an appropriate recess in which the orbital margin seats,the devices will lock themselves in position as they are expanded wherethe patient presents with orbital geometry that is normal or similar tonormal in this respect.

Use of the intraorbital expanding device of the present inventionpermits continual expansion without the need for removal and serialplacement of new prostheses. Furthermore, the devices include structuresor geometry for retention that prevent extrusion. As explained above,such structures include either acrylic projections that lodge in theintraorbital bone and/or into notches or drill holes made by theinserting surgeon, and/or by metallic stapling devices pinned againstand into the orbital bone.

E. Intraorbital, Buccal Tissue Expanding Device

Patients with vestibular tissue deficiency secondary to burns, trauma,tumor resection, mandibular atrophy secondary to loss of teeth, and avariety of other causes often require vestibuloplasty. This may belimited to the anterior region or the posterior vestibule. This may berelated both to the mandibular, lower buccal sulcus, and the maxillaryupper buccal sulcus. Patients with congenital deformities such as cleftlip and palate and other craniofacial deformities may also have tissuedeficiencies in these areas. Current treatment involves avestibuloplasty by releasing the scarred and contracted vestibulartissue and bringing in new tissue either by means of rotation flaps ortissue grafting or free tissue transfer. Following correction ofvestibular tissue deficiencies, and intraoral stent is usuallymanufactured and placed. Often this is fixated to the teeth by means ofstainless steel clasps and occasionally a variety of other fixationdevices, usually circa mandibular and/or maxillary suspension wires. Thestent itself is typically left in for prolonged periods in order toprevent contraction of the newly introduced tissue and recurrence of theoriginal problem. Such devices are either not adjustable or are noteasily adjusted.

Another embodiment of the present invention is an intraoral, buccaltissue expanding device. Such a device may be used followingvestibuloplasty, grafting, free tissue transfer, as a preliminaryexpanding device, or as the sole means of tissue expansion. The detailsof the appropriate structure for buccal tissue expanding device will, asis the case with the other embodiments of the present inventiondescribed above, depend on the particular needs of the patient for whomthe device is made.

Exemplary mandibular device is bilaterally symmetrical and thereforewill be described primarily by reference to one side, in this case theright side. A tooth stent forms the first transmitting means is bondedto the mandibular teeth and is connected through a triple-actingexpansion mechanism forming the expansion means to a posterior tissueexpanding stent and an anterior tissue expanding plate that serve as thesecond transmitting means. A curved buccal tissue expanding stent isattached to the anterior expanding plate or stent. The device isattached to the teeth by bonding or cementing the tooth stent to themandibular teeth so that the stents press against the new vestibulartissue.

Rotation of screw in expansion mechanism causes lateral movement ofposterior and anterior tissue expanding stents to permit exertion ofdesired pressure on adjacent tissue. Rotation of double-acting screw inexpansion mechanism causes posterior movement of posterior tissueexpanding stent and anterior movement of both anterior tissue expandingstent and buccal tissue expanding stent. Such adjustment of thepositions of stents results in active tissue expansion to preventcontraction of newly introduced vestibular tissues.

EXAMPLES EXAMPLE I Biodegradable Distraction Device for use inMandibular Distraction, LeFort III Distraction, Le Forte I Distractionor Monobloc Distraction Methods

As depicted in FIGS 1-6, the present invention can be used in a widevariety of distraction surgical methods and procedures. Although some ofthe components of the device in FIGS. 1-6, are represented metal orother non-biodegradable, bioerodible or bioresorbable materials,biodegradable, bioerodible or bioresorbable materials can be used forany of these components. Preferably, the activating means 22 is not madeof such biodegradable, bioerodible or bioresorbable materials, but thatneed not be the case. The activating device 22 is depicted without aturn-key, which when turned one rotation clockwise results in adistraction of about 0.5 mm.

A variety of surgical procedures may employ the internal biodegradabledistraction device of the present invention including for examplemonobloc distraction with and without facial bipartition and otherosteotomies, LeFort III distraction with or without subcranial facialbipartition, LeFort II, LeFort I, zygomatic and mandibular distraction.Since the system is biodegradable additional substantial surgicalprocedures will not be required to remove the implanted device. Thefollowing is a general description of a distraction procedure using oneaspect of a distraction device of the present invention.

A bioerodible polymer mesh (Maropore, Inc. San Diego, Calif.) isutilized to secure the device to bone. The mesh is attached to eitherside of the metallic screw of the expansion mechanism by bioerodibleslots that retain the footplate of the metallic screw. The bioerodibleslots in turn are attached to the mesh with biodegradable screws. Themesh is heat malleable, consequently it may be cut and contoured to fitvirtually any anatomical site. Standard osteotomies are performed. Theosteonomy is spanned with the distractor that is attached to the bonewith biodegradable mesh and screws. Test distraction is performed todetermine the total distraction distance and to ensure that there is noevidence of detachment of the biodegradable mesh and screws. Testdistraction also enables the surgeon to determine if the osteotomy iscomplete and the bone segment to be transported is fully mobilized.

Distraction is initiated on post-operative days 5-7 and carried out atapproximately 1.0 mm per day divided into two sessions per day.Preoperative radiologic and clinical findings dictate the extent ofdistraction. Intraoperative test distraction also enables the surgeon todetermine the extent of distraction that will be necessary forcorrection of the particular deformity. Careful postoperative follow-upenables the surgeon to determine when distraction is complete. Unlikethe large exposure that is necessary to remove metallic screws, thebiodegradable device permits easier removal if necessary. The metallicdistraction screw that is activated and driven by an external cablesheathed in TEFLON is turned counterclockwise. The footplates of thedistraction screw slide out of the biodegradable slots. The mesh doesnot require removal and usually degrades within about 18 to 36 monthsafter implantation. Once distraction is complete the metallicdistraction screw is rotated clockwise until it is disengaged from thedistraction footplate and removed from the patient. Under direct orendoscopic exposure, a new bioerodible stabilizer is placed into theanterior biodegradable slot of the attachment part which is attached tothe biodegradable mesh or plate and screwed into the posterior bonesegment. This permits earlier removal of the device and rigidstabilization of the osteotomies and distraction callus, permitting bonyconsolidation. All wounds are closed under standard medical procedures.

FIG. 4 depicts as region of a skull that has undergone an osteotomy tofully free a portion of the “cheek bone.” This freed region is theregion to be distracted during the procedure. As shown in FIG. 1 depictstwo portions of a transmitting means includes a macroporous sheet 32 ofPLA/PGA and a flange-engaging structure 34 suitable for engaging aflange of an expansion means 12. In this aspect of the present inventionthe first transmitting means 10A and the second transmitting means 10Bhave substantially similar structures. The particular structures of theflange-engaging structure 34 is provided in FIGS. 6A-6C. As shown inFIG. 1 the flange-engaging structure 34 can be engaged to themacroporous sheet 32 using appropriate attaching devices 36, in thiscase bioresorbable PLA/PGA screws.

Two transmitting means 10 of FIG. 1 can be engaged with engaged with anexpansion means 12 that includes flanges that engage the flange-engagingstructures 34 of the transmitting means (FIGS 2-3). In this figure, theexpansion means 12 is depicted as being made of non-biodegradable,n-bioerodible or non-bioresorbable materials, but that need not be thecase because the expansion means can be made of such biodegradable,bioerodible or bioresorbable materials in whole or in part. As shown inFIG. 3, the nature of the engagement of the transmitting means and theexpansion means as reversible. In the pictured aspect of the presentinvention, this reversible engagement is exhibited for both the firsttransmitting means and the second transmitting means. Thus, afterdistraction is accomplished, the expansion means can be disengaged fromthe remainder of the distraction device and removed. It is relativelysimple to remove the expansion means from a subject as opposed to thetransmitting means. Thus, there is reduced amount of cumulative traumathat the subject is exposed to. The proximal transmitting means:expansion means: distal transmitting means has been trimmed andconfigured for use on the osteotomy depicted in FIG. 4. Note that theproximal transmitting means has been altered from its planarconfiguration.

The transmitting means has a heat malleable nature, and a transmittingmeans is contacted with water hot enough to induce malleability of thematerial and the shape of the material changed to conform to the shapeof the region to which it will be attached. As shown in FIG. 4, thedistraction device is depicted in place at the site of osteotomy priorto distraction. The distraction device includes heat-malleable materialsthat have been molded to the contours of the attachment points of thedistraction device. The transmitting means 10 are secured to the skullusing PLA/PGA screws in holes drilled into the bone. During adistraction procedure, the implementation of the distraction devicewould be complete. Distraction would be accomplished by engaging theexpansion means 12 with an activation means 22 to gradually increase thedistraction distance.

FIG. 5 depicts the di action device after distraction has taken place.This figure depicts a mock-up skull, thus the distraction space has notbeen filled with distraction tissue. At this point in the procedure, theexpansion means 12 would be removed by disengaging the expansion means12 from the transmitting means 10 such as by engaging the activationmeans 22 to decrease the length of the expansion device. The expansionmeans can be removed using surgical procedures, preferably endoscopicprocedures. If the expansion means is made in whole or in part ofbiodegradable, bioerodible or bioresorbable materials, then theexpansion means can optionally be removed.

Optionally, at least one stabilizer 24, 28 can be inserted into, over oraround the expansion space and appropriately secured such that thedistracted tissue is mechanically stabilized (FIG. 7 or FIG. 9). Suchstabilizer(s) are preferably made at least in part of biodegradable,bioerodible or bioresorbable material, such as PLA/PGA, preferablymacroporous PLA/PGA. In one aspect of the present invention, thestabilizing means can engage structures on the transmitting means 10A(FIG. 9). In one aspect of the present invention, the stabilizing meansof FIG. 7 and FIG. 9 can be combined. In addition, guiding means 20 canbe used during distraction or after distraction to guide or stabilizethe distraction device (FIG. 8). The guiding means is preferably made inwhole or in part of a biodegradable, bioerodable or bioresorbablematerial. As shown in FIG. 8, as preferred aspect of the presentinvention is a guiding means that engages both the first and secondtransmitting means, but that is not a requirement of the presentinvention. For example, the guiding means can be attached to a tissuestructure in proximity to the distraction site, such as bone.

In one aspect of the present invention alternative structures of FIG. 10depict a unidirectional distraction device that includes engagingstructures 18 such as those in “shark's tooth” configurations and matingstructures 16 to match the engaging structures such as indentations orholes (such those in macroporous structures) to allow substantiallyunidirectional sliding of the transmitting means and can act tostabilize the distraction device. Preferably, the engaging structuresand/or the mating structures are made in whole or in part ofbiodegradable, bioerodible or bioresorbable materials.

The engaging structures and mating structures can be provided on anyappropriate surface on a distraction device that come in contact or inclose proximity to each other. For example, the first and secondtransmitting means can be designed to overlap each other during at leasta portion of a distraction procedure. Alternatively, the expansion meanscan overlap with one or both of the first or second transmitting meansduring at least a portion of a distraction procedure.

All publications, including patent documents and scientific articles,referred to in this application and the bibliography and attachments areincorporated by reference in their entirety for all purposes to the sameextent as if each individual publication were individually incorporatedby reference.

All headings are for the convenience of the reader and should not beused to limit the meaning of the text that follows the heading, unlessso specified.

What is claimed is:
 1. A connective tissue distraction devicecomprising: a) first transmitting means for transmitting force to afirst tissue region, b) second transmitting means for transmitting forceto a second tissue region, c) expansion means for engaging said firsttransmitting means and said second transmitting means and for exertingforce distracting said first transmitting means from said secondtransmitting means, wherein each of said first transmitting means, saidsecond transmitting means and said expansion means comprises abiodegradable, bioerodible or bioresorbable material; further whereinsaid expansion means is configured to be disengaged from said firsttransmitting means and said second transmitting means.
 2. The connectivetissue distraction device of claim 1, wherein said first transmittingmeans comprises a structure for attachment to bone.
 3. The connectivetissue distraction device of claim 2, wherein said structure forattachment to bone comprises at least in part a biodegradable,bioerodible or bioresorbable material.
 4. The connective tissuedistraction device of claim 2, wherein said structure for attachment tobone is a plate.
 5. The connective tissue distraction device of claim 2,wherein said structure for attachment to bone comprises at least onescrew.
 6. The connective tissue distraction device of claim 5, whereinsaid screw is at least in part biodegradable, bioerodible orbioresorbable material.
 7. The connective tissue distraction device ofclaim 1, wherein the second transmitting means comprises a structure forattachment to bone.
 8. The connective tissue distraction device of claim7, wherein said structure for attachment to bone is at least in part abiodegradable, bioerodible or bioresorbable material.
 9. The connectivetissue distraction device of claim 7, wherein the structure forattachment to bone is a plate.
 10. The connective tissue distractiondevice of claim 7, wherein said structure for attachment to bonecomprises at least one screw.
 11. The connective tissue distractiondevice of claim 10, wherein said screw is at least in part abiodegradable, bioerodible or bioresorbable material.
 12. The connectivetissue distraction device of claim 1, wherein at least one of the firsttransmitting means, second transmitting means or the expansion meanscomprise a malleable or heat malleable material.
 13. The connectivetissue distraction device of claim 1, wherein said first transmittingmeans is configured to transmit force to connective tissue.
 14. Theconnective tissue distraction device of claim 1, wherein said firsttransmitting means is configured to transmit force to bone.
 15. Theconnective tissue distraction device of claim 1, wherein said secondtransmitting means is configured to transmit force to connective tissue.16. The connective tissue distraction device of claim 1, wherein saidsecond transmitting means is configured to transmit force to bone. 17.The connective tissue distraction device of claim 1, wherein theexpansion means comprises a screw actuated expansion mechanism.
 18. Theconnective tissue distraction device of claim 1, further comprises anactivation means to modulate the expansion means.
 19. The connectivetissue distraction device of claim 18, wherein said activation means isdirectly or indirectly engaged with expansion means.
 20. The connectivetissue distraction device of claim 19, wherein said activation means isreversibly engaged with the expansion means.
 21. The connective tissuedistraction device of claim 1, wherein the connective tissue distractiondevice is implantable in a subject.
 22. The connective tissuedistraction device of claim 18, wherein the connective tissuedistraction device is implantable in a subject.
 23. The connectivetissue distraction device of claim 22, wherein at least a portion of theactivation means is configured to be external to the subject.
 24. Amethod of distracting a first tissue region and a second tissue region,comprising: implanting the connective tissue distraction device of claim1 into a subject and distracting the first tissue region and the secondtissue region.